1. Field of the Invention
The present invention relates in general to fuel supply devices for motor vehicles, and more particularly to the fuel supply devices of a type that supplies fuel from a fuel tank to an engine of the vehicle.
2. Description of Related Art
In motor vehicles powered by a fuel combustion engine, a fuel supply device is commonly used, which has such a configuration that components, such as, a fuel pump, a fuel filter and a pressure regulator are assembled into an integral unit with the use of a mounting bracket made of plastics, and the integral unit is mounted in a fuel tank. This type fuel supply device is shown in, for example, Japanese Patent First Provisional Publications (Tokkai Hei) No. H9-268597 and No. H11-101166.
The fuel supply device of such type is composed of a mounting bracket attached to the upper part of the fuel tank and having its lower part suspended into the fuel tank, a fuel pump attached to the lower part of the mounting bracket within the fuel tank, for discharging fuel from the fuel tank to fuel injection valves of the engine, and a pressure regulator for regulating the pressure of the fuel fed to the fuel injection valves.
The fuel pump sucks fuel from the fuel tank through its suction side and discharges the fuel toward the fuel injection valves on the engine, and the pressure regulator returns an excess part of the discharged fuel into the fuel tank to keep the pressure of the fuel led to the fuel injection valves at a constant level.
With this arrangement, should the vehicle under cruising be sharply accelerated or decelerated with only a small fuel remained in the fuel tank, the liquid surface of the fuel in the fuel tank would largely incline, so that the fuel would become insufficient around the suction side of the fuel pump. Of course, in this case, sufficient amount of fuel can not be supplied to the engine. For eliminating such drawback, in some of the vehicles, the fuel tank is formed therein with a chamber portion which defines a fuel sump around the fuel pump.
Usually, the chamber portion for the fuel sump is provided by a bottomed cylindrical casing in which the fuel pump is accommodated. In the fuel supply device, a suction pump is connected to the return side of the pressure regulator, and is located in the bottom side of the chamber portion. This suction pump sucks up fuel outside of the chamber portion with the use of fuel flowing from the return side of the pressure regulator (return fuel) so as to feed this fuel together with the return fuel into the chamber portion, so that the suction side of the fuel pump is suppressed from being exposed above from the liquid surface of fuel.
In four wheel drive vehicles or the like, there is a type using a saddle-like fuel tank including a main tank and a sub-tank in view of a restriction caused by a layout. In this connection, Japanese Patent First Provisional Publication No. H11-82209 shows a suction pump for the saddle-like fuel tank. In this case, the fuel supply device is arranged on the main tank, and the suction pump is attached to a mounting bracket. The suction pump sucks up fuel in the sub-tank by using return fuel from the pressure regulator in order to return the fuel to the main tank.
In view of the above-mentioned conventional technology, in case of application of the fuel supply device to the fuel tanks of the type having above-mentioned chamber portion, the suction pump for the chamber portion is connected to the return side of the pressure regulator. While, in case of application of the fuel supply device to the above-mentioned saddle-like fuel tank, the suction pump for the saddle-like tank is provided on the mounting bracket.
Accordingly, in the above-mentioned conventional technology, the mounting bracket for the chamber portion has a structure different from that for the saddle-like tank. Thus, various kinds of mounting brackets have to be designed and manufactured for the vehicles. Of course, in this case, components for the fuel supply device are increased and thus the productivity of the fuel supply device is lowered.
Furthermore, in case of application of the fuel supply device onto vehicles of a type in which the chamber portion is arranged in the main tank of the saddle-like tank, it is necessary to employ two suction pumps. That is, a suction pump for the chamber portion and another suction pump for the saddle-like tank are needed, which are respectively and separately provided to the mounting bracket. Of course, in this case, the mounting bracket becomes complicated in shape, and the entire construction of the fuel supply device becomes large. Furthermore, the layout for arranging the two suction pumps is difficult.
It is therefore an object of the present invention to provide a fuel supply device which is free of the above-mentioned drawbacks.
That is, according to the present invention, there is provided a fuel supply device in which two suction pumps can be easily attached to a mounting bracket, and the mounting bracket can be commonly used for both the fuel tank with a chamber portion and the saddle-like fuel tank.
According to a first aspect of the present invention, there is provided a fuel supply device for use with a fuel tank and a pressure regulator, which comprises a mounting bracket adapted to be suspended into the fuel tank; a fuel pump mounted to the mounting bracket to pump fuel from the fuel tank to the outside of the fuel tank; a fuel return passage defined by the mounting bracket, into which a part of the fuel pumped out from the fuel pump is led under operation of the pressure regulator; and first and second suction pumps mounted to the mounting bracket and sucking fuel from first and second given portions of the fuel tank by using a power possessed by the fuel led into the fuel return passage, a first passage having one end directly opened to the fuel return passage and the other end connected to the first suction pump; and a second passage having one end directly opened to the fuel return passage and the other end connected to the second suction pump.
According to a second aspect of the present invention, there is provided a fuel supply device which comprises a fuel tank for containing fuel; a mounting bracket having an upper part connected to an upper part of the fuel tank and a lower part suspended into the fuel tank; a fuel pump mounted to the lower part of the mounting bracket to pump fuel in the fuel tank to the outside of the fuel tank; a pressure regulator mounted to the lower part of the mounting bracket to regulate the pressure of fuel led to the outside of the fuel tank; a fuel return structure integral with the mounting bracket, the fuel return structure having a fuel return passage through which a part of the fuel pumped out from the fuel pump is led back into the fuel tank; first and second suction pumps for conveying fuel from first and second given portions of the fuel tank to a major portion of the fuel tank by using a power possessed by the fuel flowing in the fuel return passage of the fuel return structure; a first mounting structure integral with the mounting bracket and having the first suction pump mounted thereto, the first mounting structure having a first passage through which the fuel from the fuel return passage flows for driving the first suction pump; and a second mounting structure integral with the mounting bracket and having the second suction pump mounted thereto, the second mounting structure having a second passage through which the fuel from the fuel return passage flows for driving the second suction pump, the first and second passages being connected to the fuel return passage independently.
According to a third aspect of the present invention, there is provided a fuel supply device for use with a fuel tank, which comprises a mounting bracket adapted to be suspended into the fuel tank; a fuel pump mounted to the mounting bracket to pump fuel from the fuel tank to the outside of the fuel tank; a pressure regulator mounted to the mounting bracket to regulate the pressure of fuel led to the outside of the fuel tank by returning a part of the fuel from the fuel tank into the fuel tank; a fuel return passage defined by the mounting bracket, through which the part of the fuel pumped out from the fuel pump is led back to the fuel tank under operation of the pressure regulator; first and second suction pumps mounted to the mounting bracket and sucking fuel from first and second given portions of the fuel tank by using a power possessed by the fuel led into said fuel return passage; a first passage having one end directly opened to the fuel return passage and the other end connected to the first suction pump; and a second passage having one end directly opened to the fuel return passage and the other end connected to the second suction pump.
According to a fourth aspect of the present invention, there is provided a fuel supply device for use with a fuel tank and a pressure regulator, which comprises a mounting bracket adapted to be suspended into the fuel tank; a fuel pump mounted to the mounting bracket to pump fuel from the fuel tank to the outside of the fuel tank; a fuel return passage defined by the mounting bracket, into which a part of the fuel pumped out from the fuel pump is led under operation of the pressure regulator; first and second suction pumps mounted to the mounting bracket and sucking fuel from first and second given portions of the fuel tank by using a power possessed by the fuel led into the fuel return passage; a first passage having one end directly opened to the fuel return passage and the other end connected to the first suction pump; and a second passage having one end directly opened to the fuel return passage and the other end connected to the second suction pump.